This invention relates to gas turbine engines and particularly to its combustion section.
Within the confines of burner efficiency, allowable pressure drop and the temperature of the gas at the inlet of the turbine, the length of the burner, whether annular can or combination thereof is kept to a minimum. Obviously, the length of the burner has a direct bearing on the size of the engine case and the engine's overall length, all of which obviously bears on the engine's installed weight. For aircraft application it is of paramount importance to hold the thrust per pound of engine at as high a value as possible.
Furthermore in a high M.sub.N airflow engine, struts in the gas path along the diffuser-burner area cannot be used inasmuch as it has an adverse affect on the airflow.
We have found that we can reduce the length of heretofore known efficient burners without deteriorating any of the other operating criteria by folding the pilot burner which in turn results in stiffer rotor or rotors, a reduction in engine length and a consequential reduction in installed engine weight.